The PSTN switch off has been announced many times. What the industry is discovering, country by country, is that switching off the public switched telephone network is far harder than declaring it obsolete.
In the UK, the analogue switch-off was originally set for December 2025. It now stands at 31 January 2027, after concerns about telecare alarm users and other vulnerable customers forced a more cautious migration. Elsewhere the picture is just as staggered: some European operators have largely completed their all-IP transitions, while others are retiring copper exchange by exchange on programmes that stretch towards the end of the decade. Across Asia-Pacific, Africa and the Americas, PSTN switch off timelines vary from “already done” to “not yet scheduled.”
For network operators, there is an uncomfortable truth inside those headlines: announcing a switch-off date does not make legacy traffic disappear. Until the last line, alarm circuit, payment terminal and leased service migrates, the TDM estate underneath — local exchanges, SDH transmission, access multiplexers, signalling — has to keep working. Often for years longer than the business case ever assumed.
Why the PSTN switch off keeps slipping
Switch-off programmes slip for predictable reasons. Critical services that were never designed for IP — telecare, lift lines, utility SCADA circuits, railway signalling links — take longer to migrate safely than consumer broadband. Business customers with embedded ISDN and leased-line dependencies delay until the last possible moment. And regulators, rightly, will not allow vulnerable users to be cut off to meet an engineering deadline.
The result is a long tail. Traffic on the legacy estate falls, but the estate itself must remain fully operational, monitored and repairable. In many ways the challenge grows as migration progresses:
- The equipment gets older while OEM support contracts lapse and spare parts go end-of-sale.
- The people who know it retire. TDM, SDH and exchange-era skills are leaving the industry faster than the equipment is leaving the network.
- The internal business case shrinks. It is hard to justify permanent in-house teams for a platform that is officially “going away” — even when it will still carry critical traffic for another five years.
Running a network you’ve already decided to retire
This is where a deliberate end-of-life support strategy matters. The objective is not to extend the PSTN forever; it is to keep it reliable, safely and economically, for exactly as long as the migration requires. Three elements do most of the work:
1. A secured spares pipeline. Most switch-off-era failures are resolved by replacing a card that no one manufactures any more. A support partner holding tested, refurbished stock across the legacy vendors — Alcatel, Siemens, Ericsson, Nokia, Huawei and others — turns an end-of-sale notice from a crisis into a logistics detail.
2. Repair capability. Where spares are scarce, component-level repair and refurbishment keeps existing boards in the loop, often at a fraction of replacement cost and without the risk of untested grey-market stock.
3. Level 3 remote technical support. The hardest problem is not hardware — it is expertise. When an exchange or SDH ring develops a fault that goes beyond what Level 1 and 2 teams can resolve, someone with deep platform knowledge has to pick it up. Contracted L3 remote support puts retired-platform specialists on call 24/7, without the cost of keeping those skills on the payroll for a shrinking estate.
Supporting TDM networks through the PSTN switch off
Every operator’s migration will finish eventually. The question is what condition the legacy network — and the critical services still riding on it — will be in along the way. The operators handling the PSTN switch off well treat the remaining TDM estate not as an embarrassment to be starved of budget, but as a critical asset with a defined retirement plan: audited, spared, repairable, and backed by specialist support until the day it is finally powered down.
Carritech supports legacy voice and transmission platforms across every major vendor, with 200,000+ tested spare parts, in-house repair capability and 24/7 L3 remote technical support — helping operators worldwide keep their networks reliable all the way to the last migrated line.
Talk to us about supporting your network through the switch-off: Contact Us
